File size: 4,162 Bytes
a13d04f |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 |
package main
import (
"bufio"
"crypto/md5"
"encoding/hex"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"os"
"regexp"
"strings"
"sync"
"sync/atomic"
"time"
)
type Record struct {
URL string `json:"url"`
Text string `json:"text"`
TS string `json:"ts"`
}
var (
visited = make(map[string]bool)
visitedMu sync.RWMutex
queue = make(chan string, 1000000)
stats struct {
pages, bytes, errors int64
}
client = &http.Client{
Timeout: 5 * time.Second,
Transport: &http.Transport{
MaxIdleConns: 1000,
MaxIdleConnsPerHost: 50,
IdleConnTimeout: 30 * time.Second,
},
}
linkRe = regexp.MustCompile(`href=["']([^"']+)["']`)
scriptRe = regexp.MustCompile(`(?is)<script[^>]*>.*?</script>|<style[^>]*>.*?</style>`)
tagRe = regexp.MustCompile(`<[^>]+>`)
spaceRe = regexp.MustCompile(`\s+`)
)
func hash(s string) string {
h := md5.Sum([]byte(s))
return hex.EncodeToString(h[:8])
}
func extractText(html string) string {
text := scriptRe.ReplaceAllString(html, " ")
text = tagRe.ReplaceAllString(text, " ")
text = spaceRe.ReplaceAllString(text, " ")
text = strings.TrimSpace(text)
if len(text) > 50000 {
text = text[:50000]
}
return text
}
func extractLinks(html, baseURL string) []string {
base, err := url.Parse(baseURL)
if err != nil {
return nil
}
var links []string
matches := linkRe.FindAllStringSubmatch(html, 100)
for _, m := range matches {
if len(m) > 1 {
href := m[1]
if u, err := url.Parse(href); err == nil {
resolved := base.ResolveReference(u)
if resolved.Scheme == "http" || resolved.Scheme == "https" {
links = append(links, resolved.String())
}
}
}
}
return links
}
func worker(id int, output chan<- Record) {
for urlStr := range queue {
h := hash(urlStr)
visitedMu.RLock()
seen := visited[h]
visitedMu.RUnlock()
if seen {
continue
}
visitedMu.Lock()
visited[h] = true
visitedMu.Unlock()
resp, err := client.Get(urlStr)
if err != nil {
atomic.AddInt64(&stats.errors, 1)
continue
}
ct := resp.Header.Get("Content-Type")
if resp.StatusCode != 200 || !strings.Contains(ct, "text/html") {
resp.Body.Close()
atomic.AddInt64(&stats.errors, 1)
continue
}
body, _ := ioutil.ReadAll(io.LimitReader(resp.Body, 1<<20))
resp.Body.Close()
html := string(body)
text := extractText(html)
if len(text) > 200 {
output <- Record{URL: urlStr, Text: text, TS: time.Now().UTC().Format("2006-01-02T15:04:05")}
atomic.AddInt64(&stats.pages, 1)
atomic.AddInt64(&stats.bytes, int64(len(text)))
}
for _, link := range extractLinks(html, urlStr) {
select {
case queue <- link:
default:
}
}
}
}
func main() {
seeds := []string{
"https://en.wikipedia.org/wiki/Main_Page",
"https://en.wikipedia.org/wiki/Special:Random",
"https://news.ycombinator.com/",
"https://www.reddit.com/r/all/",
"https://www.reddit.com/r/programming/",
"https://stackoverflow.com/questions",
"https://medium.com/",
"https://dev.to/",
}
for _, s := range seeds {
queue <- s
}
os.MkdirAll("/workspace/go_crawl", 0755)
outPath := fmt.Sprintf("/workspace/go_crawl/crawl_%s.jsonl", time.Now().Format("20060102_150405"))
f, _ := os.Create(outPath)
defer f.Close()
w := bufio.NewWriter(f)
defer w.Flush()
output := make(chan Record, 10000)
go func() {
for rec := range output {
data, _ := json.Marshal(rec)
w.Write(data)
w.WriteByte('\n')
}
}()
start := time.Now()
go func() {
for {
time.Sleep(10 * time.Second)
elapsed := time.Since(start).Minutes()
if elapsed > 0 {
p := atomic.LoadInt64(&stats.pages)
b := atomic.LoadInt64(&stats.bytes)
e := atomic.LoadInt64(&stats.errors)
fmt.Printf("[%s] %d pgs | %.0fMB | %.1fMB/min | Q:%d | Err:%d\n",
time.Now().Format("15:04:05"), p, float64(b)/1024/1024, float64(b)/1024/1024/elapsed, len(queue), e)
}
}
}()
fmt.Printf("=== GO STDLIB CRAWLER ===\nWorkers: 1000\nOutput: %s\n\n", outPath)
var wg sync.WaitGroup
for i := 0; i < 1000; i++ {
wg.Add(1)
go func(id int) {
defer wg.Done()
worker(id, output)
}(i)
}
wg.Wait()
close(output)
}
|